1. Enzyme Catalysis with Catalase

2. Key Notes From Lab Handout
Enzyme: Catalase (from beef liver)
Substrate: H2O2 (hydrogen peroxide)
Stop Reaction: use sulfuric acid (H2SO4)
Quantify Amt. of H2O2 left: titrate in KMnO4
(potassium permanganate)
Baseline: Starting total amount of H2O2
FOUR ways enzyme activity can be altered:
Salt concentration (salinity)
pH (acid/base concentration)
Temperature
Activators & Inhibitors

3. Lab #3- Enzyme Catalysis w/Catalase
Three Parts to the lab:
Establish Baseline Amount of H2O2
Uncatalyzed Decomposition of H2O2
Time Trials w/Catalase to determine Rxn rate
Procedure:
10 ml H2O2 in a beaker
1.0 ml (H2O or Catalase)
10 ml 1 M H2SO4
Mix well
Take a 5 ml sample and titrate in KMnO4
Read Initial and final measurements on buret
Record Data

4. Uncatalyzed data Final reading: 11.2 ml Initial reading: 8.1 ml
Amount of KMnO4: 3.1ml

5. Sample Data Set I Amt. KMnO4(ml) 10 sec 30 sec 60 sec 90 sec. 120 sec.
Baseline
4.4
Final reading
12.0
15.3
17.4
23.1
24.4
11.5
11.6
Initial Reading
7.8
21.3
10.6
Amount KMnO4 used
4.2
3.3
2.1
1.8
1.3
0.9
0.1
Amount of H2O2 used
0.2
1.1
2.3
2.6
3.1
3.5
4.3

6. Sample Data II Amt. KMnO4(ml) 10 sec 30 sec 60 sec 90 sec. 120 sec.
Baseline
3.4
Final reading
8.6
10.2
11.2
12.2
11.5
11.6
Initial Reading
6.1
Amount KMnO4 used
2.5
1.6
1.0
0.6
0.3
0.1
0.05
(one drop)
Amount of H2O2 used
0.9
1.8
2.4
2.8
3.1
3.30
3.35

7. Conclusion Questions to Consider
Determine the amount of H2O2 in moles using the chemical equation on pg. 22 and your amount of H2O2 after 180 sec.
From Question #6, Choose two factors that can affect the rate of enzyme-catalyzed reaction of Catalase. Draw a predicted graph for each reaction.
Name two organisms that could be used to determine the reaction rate of an enzyme.
List two major sources of error and one suggestion on how to improve the lab. What would you do differently?